COQUINA n.
A soft, whitish, coral-like stone, formed of broken shells and corals, found in the southern United States, and used for roadbeds and for building material, as in the fort at St. Augustine, Florida.
CORE n.
The bony process which forms the central axis of the horns in many animals. Core box (Founding), a box or mold, usually divisible, in which cores are molded. -- Core print (Founding), a projecting piece on a pattern which forms, in the mold, an impression for holding in place or steadying a core.
CORUNDUM n.
The earth alumina, as found native in a crystalline state, including sapphire, which is the fine blue variety; the oriental ruby, or red sapphire; the oriental amethyst, or purple sapphire; and adamantine spar, the hair-brown variety. It is the hardest substance found native, next to the diamond.